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<a href="error_2error_8hpp.html">Go to the documentation of this file.</a><div class="fragment"><div class="line"><a id="l00001" name="l00001"></a><span class="lineno">    1</span><span class="comment">/* Flow</span></div>
<div class="line"><a id="l00002" name="l00002"></a><span class="lineno">    2</span><span class="comment"> * Copyright 2023 Akamai Technologies, Inc.</span></div>
<div class="line"><a id="l00003" name="l00003"></a><span class="lineno">    3</span><span class="comment"> *</span></div>
<div class="line"><a id="l00004" name="l00004"></a><span class="lineno">    4</span><span class="comment"> * Licensed under the Apache License, Version 2.0 (the</span></div>
<div class="line"><a id="l00005" name="l00005"></a><span class="lineno">    5</span><span class="comment"> * &quot;License&quot;); you may not use this file except in</span></div>
<div class="line"><a id="l00006" name="l00006"></a><span class="lineno">    6</span><span class="comment"> * compliance with the License.  You may obtain a copy</span></div>
<div class="line"><a id="l00007" name="l00007"></a><span class="lineno">    7</span><span class="comment"> * of the License at</span></div>
<div class="line"><a id="l00008" name="l00008"></a><span class="lineno">    8</span><span class="comment"> *</span></div>
<div class="line"><a id="l00009" name="l00009"></a><span class="lineno">    9</span><span class="comment"> *   https://www.apache.org/licenses/LICENSE-2.0</span></div>
<div class="line"><a id="l00010" name="l00010"></a><span class="lineno">   10</span><span class="comment"> *</span></div>
<div class="line"><a id="l00011" name="l00011"></a><span class="lineno">   11</span><span class="comment"> * Unless required by applicable law or agreed to in</span></div>
<div class="line"><a id="l00012" name="l00012"></a><span class="lineno">   12</span><span class="comment"> * writing, software distributed under the License is</span></div>
<div class="line"><a id="l00013" name="l00013"></a><span class="lineno">   13</span><span class="comment"> * distributed on an &quot;AS IS&quot; BASIS, WITHOUT WARRANTIES OR</span></div>
<div class="line"><a id="l00014" name="l00014"></a><span class="lineno">   14</span><span class="comment"> * CONDITIONS OF ANY KIND, either express or implied.</span></div>
<div class="line"><a id="l00015" name="l00015"></a><span class="lineno">   15</span><span class="comment"> * See the License for the specific language governing</span></div>
<div class="line"><a id="l00016" name="l00016"></a><span class="lineno">   16</span><span class="comment"> * permissions and limitations under the License. */</span></div>
<div class="line"><a id="l00017" name="l00017"></a><span class="lineno">   17</span><span class="comment"></span> </div>
<div class="line"><a id="l00018" name="l00018"></a><span class="lineno">   18</span><span class="comment">/// @file</span></div>
<div class="line"><a id="l00019" name="l00019"></a><span class="lineno">   19</span><span class="comment"></span><span class="preprocessor">#pragma once</span></div>
<div class="line"><a id="l00020" name="l00020"></a><span class="lineno">   20</span> </div>
<div class="line"><a id="l00021" name="l00021"></a><span class="lineno">   21</span><span class="preprocessor">#include &quot;<a class="code" href="error__fwd_8hpp.html">flow/error/error_fwd.hpp</a>&quot;</span></div>
<div class="line"><a id="l00022" name="l00022"></a><span class="lineno">   22</span><span class="preprocessor">#include &quot;<a class="code" href="log_8hpp.html">flow/log/log.hpp</a>&quot;</span></div>
<div class="line"><a id="l00023" name="l00023"></a><span class="lineno">   23</span><span class="preprocessor">#include &quot;<a class="code" href="util_2detail_2util_8hpp.html">flow/util/detail/util.hpp</a>&quot;</span></div>
<div class="line"><a id="l00024" name="l00024"></a><span class="lineno">   24</span><span class="preprocessor">#include &lt;boost/system/system_error.hpp&gt;</span></div>
<div class="line"><a id="l00025" name="l00025"></a><span class="lineno">   25</span><span class="preprocessor">#include &lt;stdexcept&gt;</span></div>
<div class="line"><a id="l00026" name="l00026"></a><span class="lineno">   26</span> </div>
<div class="line"><a id="l00027" name="l00027"></a><span class="lineno">   27</span><span class="keyword">namespace </span><a class="code hl_namespace" href="namespaceflow_1_1error.html">flow::error</a></div>
<div class="line"><a id="l00028" name="l00028"></a><span class="lineno">   28</span>{</div>
<div class="line"><a id="l00029" name="l00029"></a><span class="lineno">   29</span><span class="comment">// Types.</span></div>
<div class="line"><a id="l00030" name="l00030"></a><span class="lineno">   30</span><span class="comment"></span> </div>
<div class="line"><a id="l00031" name="l00031"></a><span class="lineno">   31</span><span class="comment">/**</span></div>
<div class="line"><a id="l00032" name="l00032"></a><span class="lineno">   32</span><span class="comment"> * An `std::runtime_error` (which is an `std::exception`) that stores an #Error_code.  We derive from boost.system&#39;s</span></div>
<div class="line"><a id="l00033" name="l00033"></a><span class="lineno">   33</span><span class="comment"> * `system_error` which already does that nicely.  This polymorphic subclass merely improves the `what()`</span></div>
<div class="line"><a id="l00034" name="l00034"></a><span class="lineno">   34</span><span class="comment"> * message a little bit -- specially handling the case when there is no #Error_code, or it is falsy -- but is</span></div>
<div class="line"><a id="l00035" name="l00035"></a><span class="lineno">   35</span><span class="comment"> * otherwise identical.</span></div>
<div class="line"><a id="l00036" name="l00036"></a><span class="lineno">   36</span><span class="comment"> *</span></div>
<div class="line"><a id="l00037" name="l00037"></a><span class="lineno">   37</span><span class="comment"> * ### Rationale ###</span></div>
<div class="line"><a id="l00038" name="l00038"></a><span class="lineno">   38</span><span class="comment"> * It is questionable whether Runtime_error is really necessary.  One can equally well simply throw</span></div>
<div class="line"><a id="l00039" name="l00039"></a><span class="lineno">   39</span><span class="comment"> * `boost::system::system_error(err_code, context)` when `bool(err_code) == true`, and</span></div>
<div class="line"><a id="l00040" name="l00040"></a><span class="lineno">   40</span><span class="comment"> * `std::runtime_error(context)` otherwise.  Indeed the user should feel 100% free to do that if desired.</span></div>
<div class="line"><a id="l00041" name="l00041"></a><span class="lineno">   41</span><span class="comment"> * flow::error::Runtime_error is mere syntactic sugar for code brevity, when one indeed has an `err_code` that may</span></div>
<div class="line"><a id="l00042" name="l00042"></a><span class="lineno">   42</span><span class="comment"> * or may not be falsy: they can just construct+throw a Runtime_error and not worry about the bifurcation.</span></div>
<div class="line"><a id="l00043" name="l00043"></a><span class="lineno">   43</span><span class="comment"> * In the end one likely just catches `std::exception exc` and logs/prints `exc.what()`: how precisely it was thrown</span></div>
<div class="line"><a id="l00044" name="l00044"></a><span class="lineno">   44</span><span class="comment"> * is of low import, typically.  Runtime_error provides a concise way (with some arguable niceties like the use</span></div>
<div class="line"><a id="l00045" name="l00045"></a><span class="lineno">   45</span><span class="comment"> * of `String_view`) to throw it when desired.</span></div>
<div class="line"><a id="l00046" name="l00046"></a><span class="lineno">   46</span><span class="comment"> */</span></div>
<div class="line"><a id="l00047" name="l00047"></a><span class="lineno"><a class="line" href="classflow_1_1error_1_1Runtime__error.html">   47</a></span><span class="keyword">class </span><a class="code hl_class" href="classflow_1_1error_1_1Runtime__error.html">Runtime_error</a> :</div>
<div class="line"><a id="l00048" name="l00048"></a><span class="lineno">   48</span>  <span class="keyword">public</span> <a class="code hl_class" href="classboost_1_1system_1_1system__error.html">boost::system::system_error</a></div>
<div class="line"><a id="l00049" name="l00049"></a><span class="lineno">   49</span>{</div>
<div class="line"><a id="l00050" name="l00050"></a><span class="lineno">   50</span><span class="keyword">public</span>:</div>
<div class="line"><a id="l00051" name="l00051"></a><span class="lineno">   51</span>  <span class="comment">// Constructors/destructor.</span></div>
<div class="line"><a id="l00052" name="l00052"></a><span class="lineno">   52</span><span class="comment"></span> </div>
<div class="line"><a id="l00053" name="l00053"></a><span class="lineno">   53</span><span class="comment">  /**</span></div>
<div class="line"><a id="l00054" name="l00054"></a><span class="lineno">   54</span><span class="comment">   * Constructs Runtime_error.</span></div>
<div class="line"><a id="l00055" name="l00055"></a><span class="lineno">   55</span><span class="comment">   *</span></div>
<div class="line"><a id="l00056" name="l00056"></a><span class="lineno">   56</span><span class="comment">   * @param err_code_or_success</span></div>
<div class="line"><a id="l00057" name="l00057"></a><span class="lineno">   57</span><span class="comment">   *        The #Error_code describing the error if available; or the success value (`Error_code()`)</span></div>
<div class="line"><a id="l00058" name="l00058"></a><span class="lineno">   58</span><span class="comment">   *        if an error code is unavailable or inapplicable to this error.</span></div>
<div class="line"><a id="l00059" name="l00059"></a><span class="lineno">   59</span><span class="comment">   *        In the latter case what() will omit anything to do with error codes and feature only `context`.</span></div>
<div class="line"><a id="l00060" name="l00060"></a><span class="lineno">   60</span><span class="comment">   * @param context</span></div>
<div class="line"><a id="l00061" name="l00061"></a><span class="lineno">   61</span><span class="comment">   *        String describing the context, i.e., where/in what circumstances the error occurred/what happened.</span></div>
<div class="line"><a id="l00062" name="l00062"></a><span class="lineno">   62</span><span class="comment">   *        For example: &quot;Peer_socket::receive()&quot; or &quot;Server_socket::accept() while checking</span></div>
<div class="line"><a id="l00063" name="l00063"></a><span class="lineno">   63</span><span class="comment">   *        state,&quot; or a string with line number and file info.  Try to keep it brief but informative.</span></div>
<div class="line"><a id="l00064" name="l00064"></a><span class="lineno">   64</span><span class="comment">   *        FLOW_UTIL_WHERE_AM_I_STR() may be helpful.</span></div>
<div class="line"><a id="l00065" name="l00065"></a><span class="lineno">   65</span><span class="comment">   */</span></div>
<div class="line"><a id="l00066" name="l00066"></a><span class="lineno">   66</span>  <span class="keyword">explicit</span> <a class="code hl_function" href="classflow_1_1error_1_1Runtime__error.html#a6c54ae5dfbfb4c53edcccee96b69bfcb">Runtime_error</a>(<span class="keyword">const</span> <a class="code hl_typedef" href="namespaceflow.html#a29eaaa9d0fac4ce87d8b969222dbed09">Error_code</a>&amp; err_code_or_success, <a class="code hl_typedef" href="namespaceflow_1_1util.html#ae4dc52186797094b3040379ff19124c9">util::String_view</a> context = <span class="stringliteral">&quot;&quot;</span>);</div>
<div class="line"><a id="l00067" name="l00067"></a><span class="lineno">   67</span><span class="comment"></span> </div>
<div class="line"><a id="l00068" name="l00068"></a><span class="lineno">   68</span><span class="comment">  /**</span></div>
<div class="line"><a id="l00069" name="l00069"></a><span class="lineno">   69</span><span class="comment">   * Constructs Runtime_error, when one only has a context string and no applicable/known error code.</span></div>
<div class="line"><a id="l00070" name="l00070"></a><span class="lineno">   70</span><span class="comment">   * Formally it&#39;s equivalent to `Runtime_error(Error_code(), context)`: it is syntactic sugar only.</span></div>
<div class="line"><a id="l00071" name="l00071"></a><span class="lineno">   71</span><span class="comment">   *</span></div>
<div class="line"><a id="l00072" name="l00072"></a><span class="lineno">   72</span><span class="comment">   * @param context</span></div>
<div class="line"><a id="l00073" name="l00073"></a><span class="lineno">   73</span><span class="comment">   *        See the other ctor.</span></div>
<div class="line"><a id="l00074" name="l00074"></a><span class="lineno">   74</span><span class="comment">   */</span></div>
<div class="line"><a id="l00075" name="l00075"></a><span class="lineno">   75</span>  <span class="keyword">explicit</span> <a class="code hl_function" href="classflow_1_1error_1_1Runtime__error.html#a6c54ae5dfbfb4c53edcccee96b69bfcb">Runtime_error</a>(<a class="code hl_typedef" href="namespaceflow_1_1util.html#ae4dc52186797094b3040379ff19124c9">util::String_view</a> context);</div>
<div class="line"><a id="l00076" name="l00076"></a><span class="lineno">   76</span> </div>
<div class="line"><a id="l00077" name="l00077"></a><span class="lineno">   77</span>  <span class="comment">// Methods.</span></div>
<div class="line"><a id="l00078" name="l00078"></a><span class="lineno">   78</span><span class="comment"></span> </div>
<div class="line"><a id="l00079" name="l00079"></a><span class="lineno">   79</span><span class="comment">  /**</span></div>
<div class="line"><a id="l00080" name="l00080"></a><span class="lineno">   80</span><span class="comment">   * Returns a message describing the exception.  Namely:</span></div>
<div class="line"><a id="l00081" name="l00081"></a><span class="lineno">   81</span><span class="comment">   *   - If no/success #Error_code passed to ctor: Message includes `context` only.</span></div>
<div class="line"><a id="l00082" name="l00082"></a><span class="lineno">   82</span><span class="comment">   *   - If non-success #Error_code passed to ctor: Message includes: numeric value of `Error_code`, a brief</span></div>
<div class="line"><a id="l00083" name="l00083"></a><span class="lineno">   83</span><span class="comment">   *     string representing the code category to which it belongs, the system message corresponding to the</span></div>
<div class="line"><a id="l00084" name="l00084"></a><span class="lineno">   84</span><span class="comment">   *     `Error_code`, and `context`.</span></div>
<div class="line"><a id="l00085" name="l00085"></a><span class="lineno">   85</span><span class="comment">   *</span></div>
<div class="line"><a id="l00086" name="l00086"></a><span class="lineno">   86</span><span class="comment">   * @return See above.</span></div>
<div class="line"><a id="l00087" name="l00087"></a><span class="lineno">   87</span><span class="comment">   */</span></div>
<div class="line"><a id="l00088" name="l00088"></a><span class="lineno">   88</span>  <span class="keyword">const</span> <span class="keywordtype">char</span>* <a class="code hl_function" href="classflow_1_1error_1_1Runtime__error.html#a97483cadd78d55c6ac8c192d6433f598">what</a>() <span class="keyword">const</span> <span class="keyword">noexcept</span> <span class="keyword">override</span>;</div>
<div class="line"><a id="l00089" name="l00089"></a><span class="lineno">   89</span> </div>
<div class="line"><a id="l00090" name="l00090"></a><span class="lineno">   90</span><span class="keyword">private</span>:</div>
<div class="line"><a id="l00091" name="l00091"></a><span class="lineno">   91</span>  <span class="comment">// Data.</span></div>
<div class="line"><a id="l00092" name="l00092"></a><span class="lineno">   92</span><span class="comment"></span> </div>
<div class="line"><a id="l00093" name="l00093"></a><span class="lineno">   93</span><span class="comment">  /**</span></div>
<div class="line"><a id="l00094" name="l00094"></a><span class="lineno">   94</span><span class="comment">   * This is a copy of `context` from ctor if `!err_code_or_success`; or unused otherwise.</span></div>
<div class="line"><a id="l00095" name="l00095"></a><span class="lineno">   95</span><span class="comment">   *</span></div>
<div class="line"><a id="l00096" name="l00096"></a><span class="lineno">   96</span><span class="comment">   * ### Rationale ###</span></div>
<div class="line"><a id="l00097" name="l00097"></a><span class="lineno">   97</span><span class="comment">   * We want what() to act as follows:</span></div>
<div class="line"><a id="l00098" name="l00098"></a><span class="lineno">   98</span><span class="comment">   *   - `!err_code_or_success`: Error codes are inapplicable; return `context` only.</span></div>
<div class="line"><a id="l00099" name="l00099"></a><span class="lineno">   99</span><span class="comment">   *   - Else: Return a string with `context`; plus all details of the error code.</span></div>
<div class="line"><a id="l00100" name="l00100"></a><span class="lineno">  100</span><span class="comment">   *</span></div>
<div class="line"><a id="l00101" name="l00101"></a><span class="lineno">  101</span><span class="comment">   * The latter occurs in our superclass `what()` already, if we pass up `context` to the super-ctor.</span></div>
<div class="line"><a id="l00102" name="l00102"></a><span class="lineno">  102</span><span class="comment">   * Now suppose `!err_code_or_success`.  No matter which super-ctor we use, it will memorize an `Error_code` --</span></div>
<div class="line"><a id="l00103" name="l00103"></a><span class="lineno">  103</span><span class="comment">   * if we pass `Error_code()` it&#39;ll remember that; if use a ctor that does not take an `Error_code()` it will</span></div>
<div class="line"><a id="l00104" name="l00104"></a><span class="lineno">  104</span><span class="comment">   * memorize its own `Error_code()`.  Therefore we must override `what()` behavior in our own what() in that case.</span></div>
<div class="line"><a id="l00105" name="l00105"></a><span class="lineno">  105</span><span class="comment">   *</span></div>
<div class="line"><a id="l00106" name="l00106"></a><span class="lineno">  106</span><span class="comment">   * Therefore this algorithm works:</span></div>
<div class="line"><a id="l00107" name="l00107"></a><span class="lineno">  107</span><span class="comment">   *   - `!err_code_or_success`: Memorize `context` in #m_context_if_no_code.  what() just returns the latter.</span></div>
<div class="line"><a id="l00108" name="l00108"></a><span class="lineno">  108</span><span class="comment">   *     Do not pass up `context`: we shall never use superclass&#39;s `what()` which is the only thing that would</span></div>
<div class="line"><a id="l00109" name="l00109"></a><span class="lineno">  109</span><span class="comment">   *     access such a thing.</span></div>
<div class="line"><a id="l00110" name="l00110"></a><span class="lineno">  110</span><span class="comment">   *   - Else: Do pass `context` up to super-constructor.  Superclass `what()` shall do the right thing.</span></div>
<div class="line"><a id="l00111" name="l00111"></a><span class="lineno">  111</span><span class="comment">   *     Do not save to `m_context_if_no_code`: our what() just forwards to superclass `what()`, so the lines</span></div>
<div class="line"><a id="l00112" name="l00112"></a><span class="lineno">  112</span><span class="comment">   *     that would ever access #m_context_if_no_code never execute.</span></div>
<div class="line"><a id="l00113" name="l00113"></a><span class="lineno">  113</span><span class="comment">   *</span></div>
<div class="line"><a id="l00114" name="l00114"></a><span class="lineno">  114</span><span class="comment">   * Note: Past versions of boost.system worked differently; it was possible to get by without this.</span></div>
<div class="line"><a id="l00115" name="l00115"></a><span class="lineno">  115</span><span class="comment">   *</span></div>
<div class="line"><a id="l00116" name="l00116"></a><span class="lineno">  116</span><span class="comment">   * ### Performance ###</span></div>
<div class="line"><a id="l00117" name="l00117"></a><span class="lineno">  117</span><span class="comment">   * Using the above algorithm `context` is copied exactly once either way: either into #m_context_if_no_code or</span></div>
<div class="line"><a id="l00118" name="l00118"></a><span class="lineno">  118</span><span class="comment">   * up into superclass&#39;s structures.  The other guy then just gets a blank string.</span></div>
<div class="line"><a id="l00119" name="l00119"></a><span class="lineno">  119</span><span class="comment">   */</span></div>
<div class="line"><a id="l00120" name="l00120"></a><span class="lineno"><a class="line" href="classflow_1_1error_1_1Runtime__error.html#a8d0d5edd8ec8e831c2eb960144c85b29">  120</a></span>  <span class="keyword">const</span> std::string <a class="code hl_variable" href="classflow_1_1error_1_1Runtime__error.html#a8d0d5edd8ec8e831c2eb960144c85b29">m_context_if_no_code</a>;</div>
<div class="line"><a id="l00121" name="l00121"></a><span class="lineno">  121</span>}; <span class="comment">// class Runtime_error</span></div>
<div class="line"><a id="l00122" name="l00122"></a><span class="lineno">  122</span> </div>
<div class="line"><a id="l00123" name="l00123"></a><span class="lineno">  123</span><span class="comment">// Free functions: in *_fwd.hpp.</span></div>
<div class="line"><a id="l00124" name="l00124"></a><span class="lineno">  124</span> </div>
<div class="line"><a id="l00125" name="l00125"></a><span class="lineno">  125</span><span class="comment">// Template implementations.</span></div>
<div class="line"><a id="l00126" name="l00126"></a><span class="lineno">  126</span> </div>
<div class="line"><a id="l00127" name="l00127"></a><span class="lineno">  127</span><span class="keyword">template</span>&lt;<span class="keyword">typename</span> Func, <span class="keyword">typename</span> Ret&gt;</div>
<div class="line"><a id="l00128" name="l00128"></a><span class="lineno"><a class="line" href="namespaceflow_1_1error.html#aa3708bdd4ceb1a6c801f3d4a1fc10f6d">  128</a></span><span class="keywordtype">bool</span> <a class="code hl_function" href="namespaceflow_1_1error.html#aa3708bdd4ceb1a6c801f3d4a1fc10f6d">exec_and_throw_on_error</a>(<span class="keyword">const</span> Func&amp; func, Ret* ret,</div>
<div class="line"><a id="l00129" name="l00129"></a><span class="lineno">  129</span>                             <a class="code hl_typedef" href="namespaceflow.html#a29eaaa9d0fac4ce87d8b969222dbed09">Error_code</a>* err_code, <a class="code hl_typedef" href="namespaceflow_1_1util.html#ae4dc52186797094b3040379ff19124c9">util::String_view</a> context)</div>
<div class="line"><a id="l00130" name="l00130"></a><span class="lineno">  130</span>{</div>
<div class="line"><a id="l00131" name="l00131"></a><span class="lineno">  131</span>  <span class="comment">/* To really &quot;get&quot; what&#39;s happening, just pick an example invoker of the macro which invokes us.</span></div>
<div class="line"><a id="l00132" name="l00132"></a><span class="lineno">  132</span><span class="comment">   * The background is in the FLOW_ERROR_EXEC_AND_THROW_ON_ERROR() doc header; but to really picture the whole thing,</span></div>
<div class="line"><a id="l00133" name="l00133"></a><span class="lineno">  133</span><span class="comment">   * just pick an example and work through how it all fits together.</span></div>
<div class="line"><a id="l00134" name="l00134"></a><span class="lineno">  134</span><span class="comment">   *</span></div>
<div class="line"><a id="l00135" name="l00135"></a><span class="lineno">  135</span><span class="comment">   * Note: This could also be done by simply stuffing all of the below into the macro and eliminating the</span></div>
<div class="line"><a id="l00136" name="l00136"></a><span class="lineno">  136</span><span class="comment">   * present function.  Well, we don&#39;t roll that way: we like debugger-friendliness, etc., etc.</span></div>
<div class="line"><a id="l00137" name="l00137"></a><span class="lineno">  137</span><span class="comment">   * We use the preprocessor ONLY when what it provides cannot be done without it. */</span></div>
<div class="line"><a id="l00138" name="l00138"></a><span class="lineno">  138</span> </div>
<div class="line"><a id="l00139" name="l00139"></a><span class="lineno">  139</span>  <span class="keywordflow">if</span> (err_code)</div>
<div class="line"><a id="l00140" name="l00140"></a><span class="lineno">  140</span>  {</div>
<div class="line"><a id="l00141" name="l00141"></a><span class="lineno">  141</span>    <span class="comment">/* All good: the caller can assume non-null err_code; can perform func() equivalent and set *err_code on error.</span></div>
<div class="line"><a id="l00142" name="l00142"></a><span class="lineno">  142</span><span class="comment">     * Our Runtime_error-throwing wrapping services are not required. */</span></div>
<div class="line"><a id="l00143" name="l00143"></a><span class="lineno">  143</span>    <span class="keywordflow">return</span> <span class="keyword">false</span>;</div>
<div class="line"><a id="l00144" name="l00144"></a><span class="lineno">  144</span>  }</div>
<div class="line"><a id="l00145" name="l00145"></a><span class="lineno">  145</span> </div>
<div class="line"><a id="l00146" name="l00146"></a><span class="lineno">  146</span>  <span class="comment">/* err_code is null, so we have to make our own Error_code and throw an error if the wrapped operation actually</span></div>
<div class="line"><a id="l00147" name="l00147"></a><span class="lineno">  147</span><span class="comment">   * sets it (indicating an error occurred). */</span></div>
<div class="line"><a id="l00148" name="l00148"></a><span class="lineno">  148</span>  <a class="code hl_typedef" href="namespaceflow.html#a29eaaa9d0fac4ce87d8b969222dbed09">Error_code</a> our_err_code;</div>
<div class="line"><a id="l00149" name="l00149"></a><span class="lineno">  149</span> </div>
<div class="line"><a id="l00150" name="l00150"></a><span class="lineno">  150</span>  <span class="comment">/* Side note: It is assumed (but we don&#39;t enforce) that func() is the same as what would execute above in the</span></div>
<div class="line"><a id="l00151" name="l00151"></a><span class="lineno">  151</span><span class="comment">   * `return false;` case.  That&#39;s why typically the caller (usually an API; say, F(a, b, ..., err_code)) would</span></div>
<div class="line"><a id="l00152" name="l00152"></a><span class="lineno">  152</span><span class="comment">   * use lambda/bind() to maka a functor F(e_c) that executes F(a, b, ..., e_c).</span></div>
<div class="line"><a id="l00153" name="l00153"></a><span class="lineno">  153</span><span class="comment">   * So here we pass our_err_code as &quot;e_c.&quot; */</span></div>
<div class="line"><a id="l00154" name="l00154"></a><span class="lineno">  154</span>  *ret = func(&amp;our_err_code);</div>
<div class="line"><a id="l00155" name="l00155"></a><span class="lineno">  155</span> </div>
<div class="line"><a id="l00156" name="l00156"></a><span class="lineno">  156</span>  <span class="keywordflow">if</span> (our_err_code)</div>
<div class="line"><a id="l00157" name="l00157"></a><span class="lineno">  157</span>  {</div>
<div class="line"><a id="l00158" name="l00158"></a><span class="lineno">  158</span>    <span class="comment">/* Error was detected: do our duty.  Pass through the context info from caller.</span></div>
<div class="line"><a id="l00159" name="l00159"></a><span class="lineno">  159</span><span class="comment">     * Note that passing in, say, FLOW_UTIL_WHERE_AM_I() would be less useful, since the present location</span></div>
<div class="line"><a id="l00160" name="l00160"></a><span class="lineno">  160</span><span class="comment">     * is not helpful to the log reader in determining where the actual error first occurred. */</span></div>
<div class="line"><a id="l00161" name="l00161"></a><span class="lineno">  161</span>    <span class="keywordflow">throw</span> <a class="code hl_class" href="classflow_1_1error_1_1Runtime__error.html">Runtime_error</a>(our_err_code, context);</div>
<div class="line"><a id="l00162" name="l00162"></a><span class="lineno">  162</span>  }</div>
<div class="line"><a id="l00163" name="l00163"></a><span class="lineno">  163</span> </div>
<div class="line"><a id="l00164" name="l00164"></a><span class="lineno">  164</span>  <span class="keywordflow">return</span> <span class="keyword">true</span>;</div>
<div class="line"><a id="l00165" name="l00165"></a><span class="lineno">  165</span>} <span class="comment">// exec_and_throw_on_error()</span></div>
<div class="line"><a id="l00166" name="l00166"></a><span class="lineno">  166</span> </div>
<div class="line"><a id="l00167" name="l00167"></a><span class="lineno">  167</span><span class="keyword">template</span>&lt;<span class="keyword">typename</span> Func&gt;</div>
<div class="line"><a id="l00168" name="l00168"></a><span class="lineno"><a class="line" href="namespaceflow_1_1error.html#a48afa7f8c2e100acd461365dfb00a114">  168</a></span><span class="keywordtype">bool</span> <a class="code hl_function" href="namespaceflow_1_1error.html#a48afa7f8c2e100acd461365dfb00a114">exec_void_and_throw_on_error</a>(<span class="keyword">const</span> Func&amp; func, <a class="code hl_typedef" href="namespaceflow.html#a29eaaa9d0fac4ce87d8b969222dbed09">Error_code</a>* err_code, <a class="code hl_typedef" href="namespaceflow_1_1util.html#ae4dc52186797094b3040379ff19124c9">util::String_view</a> context)</div>
<div class="line"><a id="l00169" name="l00169"></a><span class="lineno">  169</span>{</div>
<div class="line"><a id="l00170" name="l00170"></a><span class="lineno">  170</span>  <span class="comment">// See exec_and_throw_on_error().  This is just a simplified version where func() returns void.</span></div>
<div class="line"><a id="l00171" name="l00171"></a><span class="lineno">  171</span> </div>
<div class="line"><a id="l00172" name="l00172"></a><span class="lineno">  172</span>  <span class="keywordflow">if</span> (err_code)</div>
<div class="line"><a id="l00173" name="l00173"></a><span class="lineno">  173</span>  {</div>
<div class="line"><a id="l00174" name="l00174"></a><span class="lineno">  174</span>    <span class="keywordflow">return</span> <span class="keyword">false</span>;</div>
<div class="line"><a id="l00175" name="l00175"></a><span class="lineno">  175</span>  }</div>
<div class="line"><a id="l00176" name="l00176"></a><span class="lineno">  176</span> </div>
<div class="line"><a id="l00177" name="l00177"></a><span class="lineno">  177</span>  <a class="code hl_typedef" href="namespaceflow.html#a29eaaa9d0fac4ce87d8b969222dbed09">Error_code</a> our_err_code;</div>
<div class="line"><a id="l00178" name="l00178"></a><span class="lineno">  178</span>  func(&amp;our_err_code);</div>
<div class="line"><a id="l00179" name="l00179"></a><span class="lineno">  179</span> </div>
<div class="line"><a id="l00180" name="l00180"></a><span class="lineno">  180</span>  <span class="keywordflow">if</span> (our_err_code)</div>
<div class="line"><a id="l00181" name="l00181"></a><span class="lineno">  181</span>  {</div>
<div class="line"><a id="l00182" name="l00182"></a><span class="lineno">  182</span>    <span class="keywordflow">throw</span> <a class="code hl_class" href="classflow_1_1error_1_1Runtime__error.html">Runtime_error</a>(our_err_code, context);</div>
<div class="line"><a id="l00183" name="l00183"></a><span class="lineno">  183</span>  }</div>
<div class="line"><a id="l00184" name="l00184"></a><span class="lineno">  184</span> </div>
<div class="line"><a id="l00185" name="l00185"></a><span class="lineno">  185</span>  <span class="keywordflow">return</span> <span class="keyword">true</span>;</div>
<div class="line"><a id="l00186" name="l00186"></a><span class="lineno">  186</span>} <span class="comment">// exec_void_and_throw_on_error()</span></div>
<div class="line"><a id="l00187" name="l00187"></a><span class="lineno">  187</span> </div>
<div class="line"><a id="l00188" name="l00188"></a><span class="lineno">  188</span>} <span class="comment">// namespace flow::error</span></div>
<div class="line"><a id="l00189" name="l00189"></a><span class="lineno">  189</span> </div>
<div class="line"><a id="l00190" name="l00190"></a><span class="lineno">  190</span><span class="comment">// Macros.</span></div>
<div class="line"><a id="l00191" name="l00191"></a><span class="lineno">  191</span><span class="comment"></span> </div>
<div class="line"><a id="l00192" name="l00192"></a><span class="lineno">  192</span><span class="comment">/**</span></div>
<div class="line"><a id="l00193" name="l00193"></a><span class="lineno">  193</span><span class="comment"> * Sets `*err_code` to `ARG_val` and logs a warning about the error using FLOW_LOG_WARNING().</span></div>
<div class="line"><a id="l00194" name="l00194"></a><span class="lineno">  194</span><span class="comment"> * An `err_code` variable of type that is pointer to flow::Error_code must be declared at the point where the macro is</span></div>
<div class="line"><a id="l00195" name="l00195"></a><span class="lineno">  195</span><span class="comment"> * invoked.</span></div>
<div class="line"><a id="l00196" name="l00196"></a><span class="lineno">  196</span><span class="comment"> *</span></div>
<div class="line"><a id="l00197" name="l00197"></a><span class="lineno">  197</span><span class="comment"> * @param ARG_val</span></div>
<div class="line"><a id="l00198" name="l00198"></a><span class="lineno">  198</span><span class="comment"> *        Value convertible to flow::Error_code.  Reminder: `Error_code` is trivially/implicitly convertible from</span></div>
<div class="line"><a id="l00199" name="l00199"></a><span class="lineno">  199</span><span class="comment"> *        any error code set (such as `errno`s and boost.asio network error code set) that has been</span></div>
<div class="line"><a id="l00200" name="l00200"></a><span class="lineno">  200</span><span class="comment"> *        boost.system-enabled.</span></div>
<div class="line"><a id="l00201" name="l00201"></a><span class="lineno">  201</span><span class="comment"> */</span></div>
<div class="line"><a id="l00202" name="l00202"></a><span class="lineno"><a class="line" href="error_2error_8hpp.html#ab6b8ed79012c994cfc381e0b92c066fd">  202</a></span><span class="preprocessor">#define FLOW_ERROR_EMIT_ERROR(ARG_val) \</span></div>
<div class="line"><a id="l00203" name="l00203"></a><span class="lineno">  203</span><span class="preprocessor">  FLOW_UTIL_SEMICOLON_SAFE \</span></div>
<div class="line"><a id="l00204" name="l00204"></a><span class="lineno">  204</span><span class="preprocessor">  ( \</span></div>
<div class="line"><a id="l00205" name="l00205"></a><span class="lineno">  205</span><span class="preprocessor">    ::flow::Error_code FLOW_ERROR_EMIT_ERR_val(ARG_val); \</span></div>
<div class="line"><a id="l00206" name="l00206"></a><span class="lineno">  206</span><span class="preprocessor">    FLOW_LOG_WARNING(&quot;Error code emitted: [&quot;</span> &lt;&lt; FLOW_ERROR_EMIT_ERR_val &lt;&lt; &quot;] &quot; \</div>
<div class="line"><a id="l00207" name="l00207"></a><span class="lineno">  207</span>                     &quot;[&quot; &lt;&lt; FLOW_ERROR_EMIT_ERR_val.message() &lt;&lt; &quot;].&quot;); \</div>
<div class="line"><a id="l00208" name="l00208"></a><span class="lineno">  208</span>    *err_code = FLOW_ERROR_EMIT_ERR_val; \</div>
<div class="line"><a id="l00209" name="l00209"></a><span class="lineno">  209</span>  )</div>
<div class="line"><a id="l00210" name="l00210"></a><span class="lineno">  210</span><span class="comment"></span> </div>
<div class="line"><a id="l00211" name="l00211"></a><span class="lineno">  211</span><span class="comment">/**</span></div>
<div class="line"><a id="l00212" name="l00212"></a><span class="lineno">  212</span><span class="comment"> * Identical to FLOW_ERROR_EMIT_ERROR(), but the message logged has flow::log::Sev::S_INFO severity instead of</span></div>
<div class="line"><a id="l00213" name="l00213"></a><span class="lineno">  213</span><span class="comment"> * `S_WARNING`.</span></div>
<div class="line"><a id="l00214" name="l00214"></a><span class="lineno">  214</span><span class="comment"> *</span></div>
<div class="line"><a id="l00215" name="l00215"></a><span class="lineno">  215</span><span class="comment"> * @param ARG_val</span></div>
<div class="line"><a id="l00216" name="l00216"></a><span class="lineno">  216</span><span class="comment"> *        See FLOW_ERROR_EMIT_ERROR().</span></div>
<div class="line"><a id="l00217" name="l00217"></a><span class="lineno">  217</span><span class="comment"> */</span></div>
<div class="line"><a id="l00218" name="l00218"></a><span class="lineno"><a class="line" href="error_2error_8hpp.html#adc17094d4b9421abd04b90caab8b8e72">  218</a></span><span class="preprocessor">#define FLOW_ERROR_EMIT_ERROR_LOG_INFO(ARG_val) \</span></div>
<div class="line"><a id="l00219" name="l00219"></a><span class="lineno">  219</span><span class="preprocessor">  FLOW_UTIL_SEMICOLON_SAFE \</span></div>
<div class="line"><a id="l00220" name="l00220"></a><span class="lineno">  220</span><span class="preprocessor">  ( \</span></div>
<div class="line"><a id="l00221" name="l00221"></a><span class="lineno">  221</span><span class="preprocessor">    ::flow::Error_code FLOW_ERROR_EMIT_ERR_LOG_val(ARG_val); \</span></div>
<div class="line"><a id="l00222" name="l00222"></a><span class="lineno">  222</span><span class="preprocessor">    FLOW_LOG_INFO(&quot;Error code emitted: [&quot;</span> &lt;&lt; FLOW_ERROR_EMIT_ERR_LOG_val &lt;&lt; &quot;] &quot; \</div>
<div class="line"><a id="l00223" name="l00223"></a><span class="lineno">  223</span>                  &quot;[&quot; &lt;&lt; FLOW_ERROR_EMIT_ERR_LOG_val.message() &lt;&lt; &quot;].&quot;); \</div>
<div class="line"><a id="l00224" name="l00224"></a><span class="lineno">  224</span>    *err_code = FLOW_ERROR_EMIT_ERR_LOG_val; \</div>
<div class="line"><a id="l00225" name="l00225"></a><span class="lineno">  225</span>  )</div>
<div class="line"><a id="l00226" name="l00226"></a><span class="lineno">  226</span><span class="comment"></span> </div>
<div class="line"><a id="l00227" name="l00227"></a><span class="lineno">  227</span><span class="comment">/**</span></div>
<div class="line"><a id="l00228" name="l00228"></a><span class="lineno">  228</span><span class="comment"> * Logs a warning about the given error code using FLOW_LOG_WARNING().</span></div>
<div class="line"><a id="l00229" name="l00229"></a><span class="lineno">  229</span><span class="comment"> *</span></div>
<div class="line"><a id="l00230" name="l00230"></a><span class="lineno">  230</span><span class="comment"> * @param ARG_val</span></div>
<div class="line"><a id="l00231" name="l00231"></a><span class="lineno">  231</span><span class="comment"> *        See FLOW_ERROR_EMIT_ERROR().</span></div>
<div class="line"><a id="l00232" name="l00232"></a><span class="lineno">  232</span><span class="comment"> */</span></div>
<div class="line"><a id="l00233" name="l00233"></a><span class="lineno"><a class="line" href="error_2error_8hpp.html#a5d44fa375b0080a95f45f664c0407c72">  233</a></span><span class="preprocessor">#define FLOW_ERROR_LOG_ERROR(ARG_val) \</span></div>
<div class="line"><a id="l00234" name="l00234"></a><span class="lineno">  234</span><span class="preprocessor">  FLOW_UTIL_SEMICOLON_SAFE \</span></div>
<div class="line"><a id="l00235" name="l00235"></a><span class="lineno">  235</span><span class="preprocessor">  ( \</span></div>
<div class="line"><a id="l00236" name="l00236"></a><span class="lineno">  236</span><span class="preprocessor">    ::flow::Error_code FLOW_ERROR_LOG_ERR_val(ARG_val); \</span></div>
<div class="line"><a id="l00237" name="l00237"></a><span class="lineno">  237</span><span class="preprocessor">    FLOW_LOG_WARNING(&quot;Error occurred: [&quot;</span> &lt;&lt; FLOW_ERROR_LOG_ERR_val &lt;&lt; &quot;] &quot; \</div>
<div class="line"><a id="l00238" name="l00238"></a><span class="lineno">  238</span>                     &quot;[&quot; &lt;&lt; FLOW_ERROR_LOG_ERR_val.message() &lt;&lt; &quot;].&quot;); \</div>
<div class="line"><a id="l00239" name="l00239"></a><span class="lineno">  239</span>  )</div>
<div class="line"><a id="l00240" name="l00240"></a><span class="lineno">  240</span><span class="comment"></span> </div>
<div class="line"><a id="l00241" name="l00241"></a><span class="lineno">  241</span><span class="comment">/**</span></div>
<div class="line"><a id="l00242" name="l00242"></a><span class="lineno">  242</span><span class="comment"> * Logs a warning about the (often `errno`-based or from a library) error code in `sys_err_code`.</span></div>
<div class="line"><a id="l00243" name="l00243"></a><span class="lineno">  243</span><span class="comment"> * `sys_err_code` must be an object of type flow::Error_code in the context of the macro&#39;s invocation.</span></div>
<div class="line"><a id="l00244" name="l00244"></a><span class="lineno">  244</span><span class="comment"> * See also FLOW_ERROR_SYS_ERROR_LOG_FATAL().</span></div>
<div class="line"><a id="l00245" name="l00245"></a><span class="lineno">  245</span><span class="comment"> *</span></div>
<div class="line"><a id="l00246" name="l00246"></a><span class="lineno">  246</span><span class="comment"> * Note this implies a convention wherein system (especially `errno`-based or from a libary) error codes are to</span></div>
<div class="line"><a id="l00247" name="l00247"></a><span class="lineno">  247</span><span class="comment"> * be saved into a stack variable or parameter `flow::Error_code sys_err_code`.  Of course if you don&#39;t like this</span></div>
<div class="line"><a id="l00248" name="l00248"></a><span class="lineno">  248</span><span class="comment"> * convention and/or this error message, it is trivial to log something manually.</span></div>
<div class="line"><a id="l00249" name="l00249"></a><span class="lineno">  249</span><span class="comment"> *</span></div>
<div class="line"><a id="l00250" name="l00250"></a><span class="lineno">  250</span><span class="comment"> * It&#39;s a functional macro despite taking no arguments to convey that it mimics a `void` free function.</span></div>
<div class="line"><a id="l00251" name="l00251"></a><span class="lineno">  251</span><span class="comment"> *</span></div>
<div class="line"><a id="l00252" name="l00252"></a><span class="lineno">  252</span><span class="comment"> * The recommended (but in no way enforced or mandatory) pattern is something like:</span></div>
<div class="line"><a id="l00253" name="l00253"></a><span class="lineno">  253</span><span class="comment"> *</span></div>
<div class="line"><a id="l00254" name="l00254"></a><span class="lineno">  254</span><span class="comment"> *   ~~~</span></div>
<div class="line"><a id="l00255" name="l00255"></a><span class="lineno">  255</span><span class="comment"> *   Error_code sys_err_code;</span></div>
<div class="line"><a id="l00256" name="l00256"></a><span class="lineno">  256</span><span class="comment"> *</span></div>
<div class="line"><a id="l00257" name="l00257"></a><span class="lineno">  257</span><span class="comment"> *   // ...</span></div>
<div class="line"><a id="l00258" name="l00258"></a><span class="lineno">  258</span><span class="comment"> *</span></div>
<div class="line"><a id="l00259" name="l00259"></a><span class="lineno">  259</span><span class="comment"> *   // sys_err_code has been set to truthy value.  Decision has therefore been made to log about it but otherwise</span></div>
<div class="line"><a id="l00260" name="l00260"></a><span class="lineno">  260</span><span class="comment"> *   // recover and continue algorithm.</span></div>
<div class="line"><a id="l00261" name="l00261"></a><span class="lineno">  261</span><span class="comment"> *</span></div>
<div class="line"><a id="l00262" name="l00262"></a><span class="lineno">  262</span><span class="comment"> *   FLOW_LOG_WARNING(&quot;(...Explain what went wrong; output values of interest; but not `sys_err_code` since....)  &quot;</span></div>
<div class="line"><a id="l00263" name="l00263"></a><span class="lineno">  263</span><span class="comment"> *                    &quot;Details follow.&quot;);</span></div>
<div class="line"><a id="l00264" name="l00264"></a><span class="lineno">  264</span><span class="comment"> *   FLOW_ERROR_SYS_ERROR_LOG_WARNING();</span></div>
<div class="line"><a id="l00265" name="l00265"></a><span class="lineno">  265</span><span class="comment"> *</span></div>
<div class="line"><a id="l00266" name="l00266"></a><span class="lineno">  266</span><span class="comment"> *   // Continue operating.  No assert(false); no std::abort()....</span></div>
<div class="line"><a id="l00267" name="l00267"></a><span class="lineno">  267</span><span class="comment"> *   ~~~</span></div>
<div class="line"><a id="l00268" name="l00268"></a><span class="lineno">  268</span><span class="comment"> */</span></div>
<div class="line"><a id="l00269" name="l00269"></a><span class="lineno"><a class="line" href="error_2error_8hpp.html#a019ee6e90802e444572dd78d312d6e23">  269</a></span><span class="preprocessor">#define FLOW_ERROR_SYS_ERROR_LOG_WARNING() \</span></div>
<div class="line"><a id="l00270" name="l00270"></a><span class="lineno">  270</span><span class="preprocessor">  FLOW_LOG_WARNING(&quot;System error occurred: [&quot;</span> &lt;&lt; sys_err_code &lt;&lt; &quot;] [&quot; &lt;&lt; sys_err_code.message() &lt;&lt; &quot;].&quot;)</div>
<div class="line"><a id="l00271" name="l00271"></a><span class="lineno">  271</span><span class="comment"></span> </div>
<div class="line"><a id="l00272" name="l00272"></a><span class="lineno">  272</span><span class="comment">/**</span></div>
<div class="line"><a id="l00273" name="l00273"></a><span class="lineno">  273</span><span class="comment"> * Logs a log::Sev::S_FATAL message about the (often `errno`-based or from a library) error code in `sys_err_code`,</span></div>
<div class="line"><a id="l00274" name="l00274"></a><span class="lineno">  274</span><span class="comment"> * usually just before aborting the process or otherwise entering undefined-behavior land such as via `assert(false)`.</span></div>
<div class="line"><a id="l00275" name="l00275"></a><span class="lineno">  275</span><span class="comment"> * `sys_err_code` must be an object of type flow::Error_code in the context of the macro&#39;s invocation.</span></div>
<div class="line"><a id="l00276" name="l00276"></a><span class="lineno">  276</span><span class="comment"> *</span></div>
<div class="line"><a id="l00277" name="l00277"></a><span class="lineno">  277</span><span class="comment"> * This is identical to FLOW_ERROR_SYS_ERROR_LOG_WARNING(), except the message logged has FATAL severity instead</span></div>
<div class="line"><a id="l00278" name="l00278"></a><span class="lineno">  278</span><span class="comment"> * of a mere WARNING.  Notes in that macro&#39;s doc header generally apply.  However the use case is different.</span></div>
<div class="line"><a id="l00279" name="l00279"></a><span class="lineno">  279</span><span class="comment"> *</span></div>
<div class="line"><a id="l00280" name="l00280"></a><span class="lineno">  280</span><span class="comment"> * The recommended (but in no way enforced or mandatory) pattern is something like:</span></div>
<div class="line"><a id="l00281" name="l00281"></a><span class="lineno">  281</span><span class="comment"> *</span></div>
<div class="line"><a id="l00282" name="l00282"></a><span class="lineno">  282</span><span class="comment"> *   ~~~</span></div>
<div class="line"><a id="l00283" name="l00283"></a><span class="lineno">  283</span><span class="comment"> *   Error_code sys_err_code;</span></div>
<div class="line"><a id="l00284" name="l00284"></a><span class="lineno">  284</span><span class="comment"> *</span></div>
<div class="line"><a id="l00285" name="l00285"></a><span class="lineno">  285</span><span class="comment"> *   // ...</span></div>
<div class="line"><a id="l00286" name="l00286"></a><span class="lineno">  286</span><span class="comment"> *</span></div>
<div class="line"><a id="l00287" name="l00287"></a><span class="lineno">  287</span><span class="comment"> *   // sys_err_code has been set to truthy value that is completely unexpected or so unpalatable as to make</span></div>
<div class="line"><a id="l00288" name="l00288"></a><span class="lineno">  288</span><span class="comment"> *   // any attempt at recovery not worth the effort.  Decision has therefore been made to abort and/or</span></div>
<div class="line"><a id="l00289" name="l00289"></a><span class="lineno">  289</span><span class="comment"> *   // enter undefined-behavior land.</span></div>
<div class="line"><a id="l00290" name="l00290"></a><span class="lineno">  290</span><span class="comment"> *</span></div>
<div class="line"><a id="l00291" name="l00291"></a><span class="lineno">  291</span><span class="comment"> *   FLOW_LOG_FATAL(&quot;(...Explain what went wrong, and why it is very shocking; output values of interest; but not &quot;</span></div>
<div class="line"><a id="l00292" name="l00292"></a><span class="lineno">  292</span><span class="comment"> *                  &quot;`sys_err_code` since....)  Details follow.&quot;);</span></div>
<div class="line"><a id="l00293" name="l00293"></a><span class="lineno">  293</span><span class="comment"> *   FLOW_ERROR_SYS_ERROR_LOG_FATAL();</span></div>
<div class="line"><a id="l00294" name="l00294"></a><span class="lineno">  294</span><span class="comment"> *</span></div>
<div class="line"><a id="l00295" name="l00295"></a><span class="lineno">  295</span><span class="comment"> *   // Enter undefined-behavior land.</span></div>
<div class="line"><a id="l00296" name="l00296"></a><span class="lineno">  296</span><span class="comment"> *   // Different orgs/projects do different things; but a decent approach might be:</span></div>
<div class="line"><a id="l00297" name="l00297"></a><span class="lineno">  297</span><span class="comment"> *   assert(false &amp;&amp; &quot;(...Re-explain what went wrong, so it shows up in the assert-trip message on some stderr.&quot;);</span></div>
<div class="line"><a id="l00298" name="l00298"></a><span class="lineno">  298</span><span class="comment"> *   // Possibly really abort program, even if assert()s are disabled via NDEBUG.</span></div>
<div class="line"><a id="l00299" name="l00299"></a><span class="lineno">  299</span><span class="comment"> *   std::abort();</span></div>
<div class="line"><a id="l00300" name="l00300"></a><span class="lineno">  300</span><span class="comment"> *   ~~~</span></div>
<div class="line"><a id="l00301" name="l00301"></a><span class="lineno">  301</span><span class="comment"> */</span></div>
<div class="line"><a id="l00302" name="l00302"></a><span class="lineno"><a class="line" href="error_2error_8hpp.html#a718bccd9aa8110891f8b615efd42ff65">  302</a></span><span class="preprocessor">#define FLOW_ERROR_SYS_ERROR_LOG_FATAL() \</span></div>
<div class="line"><a id="l00303" name="l00303"></a><span class="lineno">  303</span><span class="preprocessor">  FLOW_LOG_FATAL(&quot;System error occurred: [&quot;</span> &lt;&lt; sys_err_code &lt;&lt; &quot;] [&quot; &lt;&lt; sys_err_code.message() &lt;&lt; &quot;].&quot;)</div>
<div class="line"><a id="l00304" name="l00304"></a><span class="lineno">  304</span><span class="comment"></span> </div>
<div class="line"><a id="l00305" name="l00305"></a><span class="lineno">  305</span><span class="comment">/**</span></div>
<div class="line"><a id="l00306" name="l00306"></a><span class="lineno">  306</span><span class="comment"> * Narrow-use macro that implements the error code/exception semantics expected of most public-facing Flow (and</span></div>
<div class="line"><a id="l00307" name="l00307"></a><span class="lineno">  307</span><span class="comment"> * Flow-like) class method APIs.  The semantics it helps implement are explained in flow::Error_code doc header.</span></div>
<div class="line"><a id="l00308" name="l00308"></a><span class="lineno">  308</span><span class="comment"> * More formally, here is how to use it:</span></div>
<div class="line"><a id="l00309" name="l00309"></a><span class="lineno">  309</span><span class="comment"> *</span></div>
<div class="line"><a id="l00310" name="l00310"></a><span class="lineno">  310</span><span class="comment"> * First, please read flow::Error_code doc header.  Next read on:</span></div>
<div class="line"><a id="l00311" name="l00311"></a><span class="lineno">  311</span><span class="comment"> *</span></div>
<div class="line"><a id="l00312" name="l00312"></a><span class="lineno">  312</span><span class="comment"> * Suppose you have an API `f()` in some class `C` that returns type `T` and promises, in its doc header,</span></div>
<div class="line"><a id="l00313" name="l00313"></a><span class="lineno">  313</span><span class="comment"> * to implement the error reporting semantics listed in the aforementioned flow::Error_code doc header.  That is, if</span></div>
<div class="line"><a id="l00314" name="l00314"></a><span class="lineno">  314</span><span class="comment"> * user passes in null `err_code`, error would cause `Run_time error(e_c)` to be thrown; if non-null, then</span></div>
<div class="line"><a id="l00315" name="l00315"></a><span class="lineno">  315</span><span class="comment"> * `*err_code = e_c` would be set sans exception -- `e_c` being the error code explaining what went wrong,</span></div>
<div class="line"><a id="l00316" name="l00316"></a><span class="lineno">  316</span><span class="comment"> * such as flow::net_flow::error::Code::S_WAIT_INTERRUPTED.  Then here&#39;s how to use the macro:</span></div>
<div class="line"><a id="l00317" name="l00317"></a><span class="lineno">  317</span><span class="comment"> *</span></div>
<div class="line"><a id="l00318" name="l00318"></a><span class="lineno">  318</span><span class="comment"> *   ~~~</span></div>
<div class="line"><a id="l00319" name="l00319"></a><span class="lineno">  319</span><span class="comment"> *   // Example API.  In this one, there&#39;s a 4th argument that happens to follow the standard Error_code* one.</span></div>
<div class="line"><a id="l00320" name="l00320"></a><span class="lineno">  320</span><span class="comment"> *   // arg2 is a (const) reference, as opposed to a pointer or scalar, and is most efficiently handled by adding</span></div>
<div class="line"><a id="l00321" name="l00321"></a><span class="lineno">  321</span><span class="comment"> *   // cref() to avoid copying it.</span></div>
<div class="line"><a id="l00322" name="l00322"></a><span class="lineno">  322</span><span class="comment"> *   T f(AT1 arg1, const AT2&amp; arg2, Error_code* err_code = 0, AT3 arg3 = 0)</span></div>
<div class="line"><a id="l00323" name="l00323"></a><span class="lineno">  323</span><span class="comment"> *   {</span></div>
<div class="line"><a id="l00324" name="l00324"></a><span class="lineno">  324</span><span class="comment"> *     FLOW_ERROR_EXEC_AND_THROW_ON_ERROR(T, // Provide the return type of the API.</span></div>
<div class="line"><a id="l00325" name="l00325"></a><span class="lineno">  325</span><span class="comment"> *                                           // Forward all the args into the macro, but replace `err_code` =&gt; `_1`.</span></div>
<div class="line"><a id="l00326" name="l00326"></a><span class="lineno">  326</span><span class="comment"> *                                        arg1, arg2, _1, arg3);</span></div>
<div class="line"><a id="l00327" name="l00327"></a><span class="lineno">  327</span><span class="comment"> *     // ^-- Call ourselves and return if err_code is null.  If got to present line, err_code is not null.</span></div>
<div class="line"><a id="l00328" name="l00328"></a><span class="lineno">  328</span><span class="comment"> *</span></div>
<div class="line"><a id="l00329" name="l00329"></a><span class="lineno">  329</span><span class="comment"> *     // ...Bulk of f() goes here!  You can now set *err_code to anything without fear....</span></div>
<div class="line"><a id="l00330" name="l00330"></a><span class="lineno">  330</span><span class="comment"> *   }</span></div>
<div class="line"><a id="l00331" name="l00331"></a><span class="lineno">  331</span><span class="comment"> *   ~~~</span></div>
<div class="line"><a id="l00332" name="l00332"></a><span class="lineno">  332</span><span class="comment"> *</span></div>
<div class="line"><a id="l00333" name="l00333"></a><span class="lineno">  333</span><span class="comment"> * @see flow::Error_code for typical error reporting semantics this macro helps implement.</span></div>
<div class="line"><a id="l00334" name="l00334"></a><span class="lineno">  334</span><span class="comment"> * @see exec_void_and_throw_on_error() which you can use directly when `ARG_ret_type` would be void.</span></div>
<div class="line"><a id="l00335" name="l00335"></a><span class="lineno">  335</span><span class="comment"> *      The present macro does not work in that case; but at that point using the function directly is concise enough.</span></div>
<div class="line"><a id="l00336" name="l00336"></a><span class="lineno">  336</span><span class="comment"> * @see exec_and_throw_on_error() which you can use directly when `T` is a reference type.</span></div>
<div class="line"><a id="l00337" name="l00337"></a><span class="lineno">  337</span><span class="comment"> *      The present macro does not work in that case.</span></div>
<div class="line"><a id="l00338" name="l00338"></a><span class="lineno">  338</span><span class="comment"> *</span></div>
<div class="line"><a id="l00339" name="l00339"></a><span class="lineno">  339</span><span class="comment"> * @param ARG_ret_type</span></div>
<div class="line"><a id="l00340" name="l00340"></a><span class="lineno">  340</span><span class="comment"> *        The return type of the invoking function/method.  It cannot be a reference type.</span></div>
<div class="line"><a id="l00341" name="l00341"></a><span class="lineno">  341</span><span class="comment"> *        In practice this would be, for example,</span></div>
<div class="line"><a id="l00342" name="l00342"></a><span class="lineno">  342</span><span class="comment"> *        `size_t` when wrapping a `receive()` (which returns # of bytes received or 0).</span></div>
<div class="line"><a id="l00343" name="l00343"></a><span class="lineno">  343</span><span class="comment"> * @param ARG_function_name</span></div>
<div class="line"><a id="l00344" name="l00344"></a><span class="lineno">  344</span><span class="comment"> *        Suppose you wanted to, via infinite recursion, call the function -- from where you use this macro --</span></div>
<div class="line"><a id="l00345" name="l00345"></a><span class="lineno">  345</span><span class="comment"> *        and would therefore write a statement of the form `return F(A1, A2, ..., err_code, ...);`.</span></div>
<div class="line"><a id="l00346" name="l00346"></a><span class="lineno">  346</span><span class="comment"> *        `ARG_function_name` shall be the `F` part of such a hypothetical statement.</span></div>
<div class="line"><a id="l00347" name="l00347"></a><span class="lineno">  347</span><span class="comment"> *        Tip: Even in non-`static` member functions (methods), just the method name -- without the class name `::`</span></div>
<div class="line"><a id="l00348" name="l00348"></a><span class="lineno">  348</span><span class="comment"> *        part -- is almost always fine.</span></div>
<div class="line"><a id="l00349" name="l00349"></a><span class="lineno">  349</span><span class="comment"> *        Tip: However template args typically do have to be forwarded (e.g., in `template&lt;typename T&gt; X::f() {}`</span></div>
<div class="line"><a id="l00350" name="l00350"></a><span class="lineno">  350</span><span class="comment"> *        you&#39;d supply `f&lt;T&gt;` as `ARG_function_name`), unless the compiler can infer them.</span></div>
<div class="line"><a id="l00351" name="l00351"></a><span class="lineno">  351</span><span class="comment"> *        Example: in a `bool X::listen(int x, Error_code* err_code, float y) {}` you&#39;d have</span></div>
<div class="line"><a id="l00352" name="l00352"></a><span class="lineno">  352</span><span class="comment"> *        `{ return listen(x, err_code, y); }` and thus `ARG_function_name` shall be just `listen`.</span></div>
<div class="line"><a id="l00353" name="l00353"></a><span class="lineno">  353</span><span class="comment"> *        Tip: But, if there are 2+ template args, and the compiler cannot infer them, you need to</span></div>
<div class="line"><a id="l00354" name="l00354"></a><span class="lineno">  354</span><span class="comment"> *        surround the `x&lt;a, b, ...&gt;` with parentheses: like: `FLOW_ERROR_EXEC_AND_THROW_ON_ERROR(int, (x&lt;a, b&gt;), ...)`.</span></div>
<div class="line"><a id="l00355" name="l00355"></a><span class="lineno">  355</span><span class="comment"> * @param ...</span></div>
<div class="line"><a id="l00356" name="l00356"></a><span class="lineno">  356</span><span class="comment"> *        First see the premise in the doc header for `ARG_function_name` just above.</span></div>
<div class="line"><a id="l00357" name="l00357"></a><span class="lineno">  357</span><span class="comment"> *        Then the `...` arg list shall be as follows:</span></div>
<div class="line"><a id="l00358" name="l00358"></a><span class="lineno">  358</span><span class="comment"> *        `A1, A2, ..., _1, ...`.  In other words it shall be the arg list for the invoking function/method as-if</span></div>
<div class="line"><a id="l00359" name="l00359"></a><span class="lineno">  359</span><span class="comment"> *        recursively calling it, but with the `err_code` arg replaced by the special identifier `_1`.</span></div>
<div class="line"><a id="l00360" name="l00360"></a><span class="lineno">  360</span><span class="comment"> *        Example: in a `bool X::listen(int x, Error_code* err_code, float y) {}` you&#39;d have</span></div>
<div class="line"><a id="l00361" name="l00361"></a><span class="lineno">  361</span><span class="comment"> *        `{ return listen(x, err_code, y); }` and thus `...` arg list shall be: `x, _1, y`.</span></div>
<div class="line"><a id="l00362" name="l00362"></a><span class="lineno">  362</span><span class="comment"> */</span></div>
<div class="line"><a id="l00363" name="l00363"></a><span class="lineno"><a class="line" href="error_2error_8hpp.html#a636b2d30a8785df6e84646b568bce9b5">  363</a></span><span class="preprocessor">#define FLOW_ERROR_EXEC_AND_THROW_ON_ERROR(ARG_ret_type, ARG_function_name, ...) \</span></div>
<div class="line"><a id="l00364" name="l00364"></a><span class="lineno">  364</span><span class="preprocessor">  FLOW_UTIL_SEMICOLON_SAFE \</span></div>
<div class="line"><a id="l00365" name="l00365"></a><span class="lineno">  365</span><span class="preprocessor">  ( \</span></div>
<div class="line"><a id="l00366" name="l00366"></a><span class="lineno">  366</span><span class="preprocessor">    </span><span class="comment">/* We need both the result of the operation (if applicable) and whether it actually ran. */</span><span class="preprocessor"> \</span></div>
<div class="line"><a id="l00367" name="l00367"></a><span class="lineno">  367</span><span class="preprocessor">    </span><span class="comment">/* So we must introduce this local variable (note it&#39;s within a { block } so should minimally interfere with */</span><span class="preprocessor"> \</span></div>
<div class="line"><a id="l00368" name="l00368"></a><span class="lineno">  368</span><span class="preprocessor">    </span><span class="comment">/* the invoker&#39;s code).  We can&#39;t use a sentinel value to combine the two, since the operation&#39;s result may */</span><span class="preprocessor"> \</span></div>
<div class="line"><a id="l00369" name="l00369"></a><span class="lineno">  369</span><span class="preprocessor">    </span><span class="comment">/* require ARG_ret_type&#39;s entire range. */</span><span class="preprocessor"> \</span></div>
<div class="line"><a id="l00370" name="l00370"></a><span class="lineno">  370</span><span class="preprocessor">    ARG_ret_type result; \</span></div>
<div class="line"><a id="l00371" name="l00371"></a><span class="lineno">  371</span><span class="preprocessor">    </span><span class="comment">/* We provide the function: f(Error_code*), where f(e_c) == ARG_function_name(..., e_c, ...). */</span><span class="preprocessor"> \</span></div>
<div class="line"><a id="l00372" name="l00372"></a><span class="lineno">  372</span><span class="preprocessor">    </span><span class="comment">/* Also supply context info of this macro&#39;s invocation spot. */</span><span class="preprocessor"> \</span></div>
<div class="line"><a id="l00373" name="l00373"></a><span class="lineno">  373</span><span class="preprocessor">    </span><span class="comment">/* Note that, if f() is executed, it may throw Runtime_error which is the point of its existence. */</span><span class="preprocessor"> \</span></div>
<div class="line"><a id="l00374" name="l00374"></a><span class="lineno">  374</span><span class="preprocessor">    if (::flow::error::exec_and_throw_on_error \</span></div>
<div class="line"><a id="l00375" name="l00375"></a><span class="lineno">  375</span><span class="preprocessor">          ([&amp;](::flow::Error_code* _1) -&gt; ARG_ret_type \</span></div>
<div class="line"><a id="l00376" name="l00376"></a><span class="lineno">  376</span><span class="preprocessor">             { return ARG_function_name(__VA_ARGS__); }, \</span></div>
<div class="line"><a id="l00377" name="l00377"></a><span class="lineno">  377</span><span class="preprocessor">           &amp;result, err_code, FLOW_UTIL_WHERE_AM_I_LITERAL(ARG_function_name))) \</span></div>
<div class="line"><a id="l00378" name="l00378"></a><span class="lineno">  378</span><span class="preprocessor">    { \</span></div>
<div class="line"><a id="l00379" name="l00379"></a><span class="lineno">  379</span><span class="preprocessor">      </span><span class="comment">/* Aforementioned f() WAS executed; did NOT throw (no error); and return value was placed into `result`. */</span><span class="preprocessor"> \</span></div>
<div class="line"><a id="l00380" name="l00380"></a><span class="lineno">  380</span><span class="preprocessor">      return result; \</span></div>
<div class="line"><a id="l00381" name="l00381"></a><span class="lineno">  381</span><span class="preprocessor">    } \</span></div>
<div class="line"><a id="l00382" name="l00382"></a><span class="lineno">  382</span><span class="preprocessor">    </span><span class="comment">/* else: */</span><span class="preprocessor"> \</span></div>
<div class="line"><a id="l00383" name="l00383"></a><span class="lineno">  383</span><span class="preprocessor">    </span><span class="comment">/* f() did not run, because err_code is non-null.  So now macro invoker should do its thing assuming that fact. */</span><span class="preprocessor"> \</span></div>
<div class="line"><a id="l00384" name="l00384"></a><span class="lineno">  384</span><span class="preprocessor">    </span><span class="comment">/* Recall that the idea is that f() is just recursively calling the method invoking this macro with the same */</span><span class="preprocessor"> \</span></div>
<div class="line"><a id="l00385" name="l00385"></a><span class="lineno">  385</span><span class="preprocessor">    </span><span class="comment">/* arguments except for the Error_code* arg, where they supply specifically `_1` by our contract. */</span><span class="preprocessor"> \</span></div>
<div class="line"><a id="l00386" name="l00386"></a><span class="lineno">  386</span><span class="preprocessor">  )</span></div>
<div class="line"><a id="l00387" name="l00387"></a><span class="lineno">  387</span> </div>
<div class="line"><a id="l00388" name="l00388"></a><span class="lineno">  388</span><span class="comment">/* Now that we&#39;re out of that macro&#39;s body with all the backslashes...</span></div>
<div class="line"><a id="l00389" name="l00389"></a><span class="lineno">  389</span><span class="comment"> * Discussion of the FLOW_UTIL_WHERE_AM_I_LITERAL(ARG_function_name) snippet above:</span></div>
<div class="line"><a id="l00390" name="l00390"></a><span class="lineno">  390</span><span class="comment"> *</span></div>
<div class="line"><a id="l00391" name="l00391"></a><span class="lineno">  391</span><span class="comment"> * Considering the potential frequency that FLOW_ERROR_EXEC_AND_THROW_ON_ERROR() is invoked in</span></div>
<div class="line"><a id="l00392" name="l00392"></a><span class="lineno">  392</span><span class="comment"> * an error-reporting API (such as flow::net_flow) -- even *without* an error actually being emitted --</span></div>
<div class="line"><a id="l00393" name="l00393"></a><span class="lineno">  393</span><span class="comment"> * it is important we do not add undue computation.  That macro does not take a context string, so it must</span></div>
<div class="line"><a id="l00394" name="l00394"></a><span class="lineno">  394</span><span class="comment"> * compute it itself; as usual we use file/function/line for this.  With the technique used above</span></div>
<div class="line"><a id="l00395" name="l00395"></a><span class="lineno">  395</span><span class="comment"> * FLOW_UTIL_WHERE_AM_I_LITERAL() is replaced by a *string literal* -- like:</span></div>
<div class="line"><a id="l00396" name="l00396"></a><span class="lineno">  396</span><span class="comment"> *   &quot;/cool/path/to/file.cpp&quot; &quot;:&quot; &quot;Class::someFunc&quot; &quot;(&quot; &quot;332&quot; &quot;)&quot;</span></div>
<div class="line"><a id="l00397" name="l00397"></a><span class="lineno">  397</span><span class="comment"> * which is as compile-time as it gets.  So perf-wise that&#39;s fantastic; as good as it gets.</span></div>
<div class="line"><a id="l00398" name="l00398"></a><span class="lineno">  398</span><span class="comment"> *</span></div>
<div class="line"><a id="l00399" name="l00399"></a><span class="lineno">  399</span><span class="comment"> * Are there weaknesses?  Yes; there is one: Per its doc header FLOW_UTIL_WHERE_AM_I_LITERAL(), due to having</span></div>
<div class="line"><a id="l00400" name="l00400"></a><span class="lineno">  400</span><span class="comment"> * to be replaced by a literal, cannot cut out &quot;/cool/path/to/&quot; from __FILE__, even though in flow.log we do so</span></div>
<div class="line"><a id="l00401" name="l00401"></a><span class="lineno">  401</span><span class="comment"> * for readability of logs.  What if we wanted to get rid of this weakness?  Then we cannot have a literal there;</span></div>
<div class="line"><a id="l00402" name="l00402"></a><span class="lineno">  402</span><span class="comment"> * we can use other, not-fully-compile-time-computed FLOW_UTIL_WHERE_AM_I*(); that means extra computation</span></div>
<div class="line"><a id="l00403" name="l00403"></a><span class="lineno">  403</span><span class="comment"> * at every call-site.  That, too, can be worked-around: One can add an exec_and_throw_on_error() overload</span></div>
<div class="line"><a id="l00404" name="l00404"></a><span class="lineno">  404</span><span class="comment"> * that would take 3 context args instead of 1: strings for file and function, int for line (supplied via</span></div>
<div class="line"><a id="l00405" name="l00405"></a><span class="lineno">  405</span><span class="comment"> * __FILE__, #ARG_function, __LINE__); and it would only actually build a context string to pass to</span></div>
<div class="line"><a id="l00406" name="l00406"></a><span class="lineno">  406</span><span class="comment"> * Runtime_error *if* (1) an error actually occurred; *and* (2) user in fact used err_code=null (meaning throw on</span></div>
<div class="line"><a id="l00407" name="l00407"></a><span class="lineno">  407</span><span class="comment"> * error as opposed to return an Error_code); so lazy-evaluation.</span></div>
<div class="line"><a id="l00408" name="l00408"></a><span class="lineno">  408</span><span class="comment"> *</span></div>
<div class="line"><a id="l00409" name="l00409"></a><span class="lineno">  409</span><span class="comment"> * That would have been a viable approach but:</span></div>
<div class="line"><a id="l00410" name="l00410"></a><span class="lineno">  410</span><span class="comment"> *   - still slower (instead of a single compile-time-known pointer, at least 2 ptrs + 1 ints are passed around</span></div>
<div class="line"><a id="l00411" name="l00411"></a><span class="lineno">  411</span><span class="comment"> *     the call stack) at each call-site;</span></div>
<div class="line"><a id="l00412" name="l00412"></a><span class="lineno">  412</span><span class="comment"> *   - much slower on exception-throwing error (albeit this being relatively rare, typically; not at each call-site);</span></div>
<div class="line"><a id="l00413" name="l00413"></a><span class="lineno">  413</span><span class="comment"> *   - much, much more impl code.</span></div>
<div class="line"><a id="l00414" name="l00414"></a><span class="lineno">  414</span><span class="comment"> *</span></div>
<div class="line"><a id="l00415" name="l00415"></a><span class="lineno">  415</span><span class="comment"> * So it&#39;s cool; just don&#39;t massage __FILE__ in a totally flow.log-consistent way. */</span></div>
<div class="ttc" id="aclassboost_1_1system_1_1system__error_html"><div class="ttname"><a href="classboost_1_1system_1_1system__error.html">boost::system::system_error</a></div></div>
<div class="ttc" id="aclassflow_1_1error_1_1Runtime__error_html"><div class="ttname"><a href="classflow_1_1error_1_1Runtime__error.html">flow::error::Runtime_error</a></div><div class="ttdoc">An std::runtime_error (which is an std::exception) that stores an Error_code.</div><div class="ttdef"><b>Definition:</b> <a href="error_2error_8hpp_source.html#l00047">error.hpp:49</a></div></div>
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<div class="ttc" id="anamespaceflow_1_1error_html"><div class="ttname"><a href="namespaceflow_1_1error.html">flow::error</a></div><div class="ttdoc">Flow module that facilitates working with error codes and exceptions; essentially comprised of niceti...</div><div class="ttdef"><b>Definition:</b> <a href="error_2error_8cpp_source.html#l00021">error.cpp:22</a></div></div>
<div class="ttc" id="anamespaceflow_1_1error_html_a48afa7f8c2e100acd461365dfb00a114"><div class="ttname"><a href="namespaceflow_1_1error.html#a48afa7f8c2e100acd461365dfb00a114">flow::error::exec_void_and_throw_on_error</a></div><div class="ttdeci">bool exec_void_and_throw_on_error(const Func &amp;func, Error_code *err_code, util::String_view context)</div><div class="ttdoc">Equivalent of exec_and_throw_on_error() for operations with void return type.</div><div class="ttdef"><b>Definition:</b> <a href="error_2error_8hpp_source.html#l00168">error.hpp:168</a></div></div>
<div class="ttc" id="anamespaceflow_1_1error_html_aa3708bdd4ceb1a6c801f3d4a1fc10f6d"><div class="ttname"><a href="namespaceflow_1_1error.html#aa3708bdd4ceb1a6c801f3d4a1fc10f6d">flow::error::exec_and_throw_on_error</a></div><div class="ttdeci">bool exec_and_throw_on_error(const Func &amp;func, Ret *ret, Error_code *err_code, util::String_view context)</div><div class="ttdoc">Helper for FLOW_ERROR_EXEC_AND_THROW_ON_ERROR() macro that does everything in the latter not needing ...</div><div class="ttdef"><b>Definition:</b> <a href="error_2error_8hpp_source.html#l00128">error.hpp:128</a></div></div>
<div class="ttc" id="anamespaceflow_1_1util_html_ae4dc52186797094b3040379ff19124c9"><div class="ttname"><a href="namespaceflow_1_1util.html#ae4dc52186797094b3040379ff19124c9">flow::util::String_view</a></div><div class="ttdeci">Basic_string_view&lt; char &gt; String_view</div><div class="ttdoc">Commonly used char-based Basic_string_view. See its doc header.</div><div class="ttdef"><b>Definition:</b> <a href="string__view_8hpp_source.html#l00191">string_view.hpp:191</a></div></div>
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